Rates of violence in substance abuse treatment (SAT) samples (e.g., > 50%) are 2-3 times higher than rates found in community samples. Violence has psychosocial, medical and psychiatric costs, and is a marker for poor response to SAT. However, treatment programs typically do not include violence prevention interventions, and very few studies have examined interventions designed to prevent violence. The objectives of this research is to develop and pilot test an Integrated Violence Prevention Treatment (IVPT) to be delivered as a supplement to substance abuse treatment. IVPT will involve the integration of Motivational Enhancement Therapy and Cognitive Behavioral Therapy. Specific aim 1 is to operationally define a promising behavioral therapy addressing violence (IVPT), delivered as an adjunct to drug abuse/dependence treatment. This will involve development and refinement of: (A) detailed IVPT treatment materials (personalized feedback session report; group session materials); (B) a detailed manual for implementing this therapy intervention; (C) a staff training protocol and measures of therapist skill and fidelity to the intervention; followed by (D) staff training to conduct the intervention; and (E) an open-trial to pilot test and refine the IVPT manual, therapist training protocol, screening and assessment procedures and measures. Specific aim 2 is to conduct a pilot study using a randomized controlled trial design to determine the efficacy of IVPT in reducing drug use and violence. The pilot also will provide preliminary information regarding patient characteristics that may moderate the impact of IVPT on such outcomes, as well estimates of the intervention effect size. Participants will be recruited and screened from outpatient substance abuse treatment programs. Those screening positive for past-year violence then will complete a detailed assessment of drug and alcohol consumption patterns, violent events experienced in the six-months pretreatment, and a structured diagnostic interview. In the development phase, participants screening positive for past-year violence will be assigned to the IVPT intervention. For the pilot study, participants will be randomized to either IVPT or a control condition (attention placebo), and will complete follow-up assessments of substance use and violence at 3 and 6 months. This study will be an important first step in the development of interventions for a costly, common and under-treated problem within SAT.